The major purpose of Project 1 is to examine linguistic and non-linguistic information processing capacities in language impaired children (ages 4-12 years). Although earlier research focussed on the language-specific nature of the deficit, recent research suggests that information processing deficits (across cognitive domains) underlie specific language impairment. We will explore these hypotheses by conducting studies of semantics, grammar, discourse and metalinguistic abilities; including real-time processing studies of grammatically, word recognition and sentence interpretation. These "on-line" measures capture the temporal aspects of language processing (i.e. when specific decisions are made, and how those decisions are affected by different kinds of contextual information). To investigate nonverbal cognition, we will conduct studies of non-linguistic processing including attention, reasoning, spatial perception and construction, and affect. The results of these studies will allow us to examine performance profiles of L1 individuals and subgroups within language domains and between language and cognitive domains for evidence of (1) underdeveloped linguistic knowledge, (2) deficits in the processing mechanisms which access this knowledge, (3) more general information processing deficits that extend beyond language into other cognitive domains, and/or (4) relationships with affect and psychosocial factors. Additionally, relationships between linguistic and cognitive abilities and brain structure and function will be examined (Projects 4 and 5).